Videos can help see how an artist actually moves their hand, or which parts they drew first, especially when some book courses kinda seem to jump ahead in their steps and not give detailed info. Some people also learn better visually and having an actual instructor show them step by step.
However, books already have everything you need if you have patience and enough attention span, and overall books will have higher quality teaching material. Only good video content generally comes from paid courses, which can be way more expensive than their book counterparts, and just like book to movie adaptations, might be missing some crucial bits.
If we talking about free shit like YouTube, good videos are one in a million, it's mostly a grift because any dumb teen who's ok at drawing can record themselves sounding like they know what they are saying, but not actually teach anything worthwhile. Even the ones who can have the occasional video end up either advising worthless crap, or repeating themselves, like Marc Brunet, who hasn't made an actual new video in 3 years and just keeps telling the same handful of advice under different titles.
TLDR: don't be a zoom, get a good book by a good artist, if said artist also has a video adaptation of their course, it's probably good too, and if you do both at the same time you'll get even more gains.